The field of the invention is the measurement of vision capabilities of a subject using functional magnetic resonance imaging (fMRI) techniques.
Functional magnetic resonance imaging (fMRI) technology provides a new approach to study neuronal activity. Conventional fMRI detects changes in cerebral blood volume, flow, and oxygenation that locally occur in association with increased neuronal activity induced by functional paradigms. As described in U.S. Pat. No. 5,603,322, an MRI system is used to acquire signals from the brain over a period of time. As the brain performs a task, these signals are modulated synchronously with task performance to reveal which regions of the brain are involved in performing the task. Much research has been done to find tasks which can be performed by patients, and which reveal in an fMRI image acquired at the same time, regions in the brain that function differently.
Functional magnetic resonance imaging has been used to create cortical maps of the retinotopic organization of human visual cortex. As described by DeYoe et al in xe2x80x9cFunctional Magnetic Resonance Imaging (fMRI) Of The Human Brainxe2x80x9d, Journal of Neuroscience Methods, 54 (1994) 171-187, an fMRI scan sequence is performed while providing a visual stimulation to the subject. An optical system is employed to provide a visual stimulus that changes in a prescribed manner during the fMRI scan sequence. Different regions of the retina were stimulated and the regions in the visual cortex which were responsive as measured by fMRI images were mapped. While the relationship between retinal stimulation and visual cortex response was thus established and is of academic value, the set of fMRI images produced by such scans are of limited clinical value.
The present invention is a method and apparatus for diagnosing brain activation information produced by an fMRI scan. More particularly, an fMRI scan is performed in which the subject is visually stimulated in accordance with a prescribed vision test and a time course image data set is acquired, and a functional field map indicative of the subject""s vision capability over the subjects""s field of view is produced. In one embodiment of the invention perceptual vision deficits are predicted from the functional field map as a result of damage to the brain.
The foregoing and other objects and advantages of the invention will appear from the following description. In the description, reference is made to the accompanying drawings which form a part hereof, and in which there is shown by way of illustration a preferred embodiment of the invention. Such embodiment does not necessarily represent the full scope of the invention, however, and reference is made therefore to the claims herein for interpreting the scope of the invention.